Nearly all business telephone systems are based on a centralized or star network design. In such a conventional system, all telephones and trunk lines converge on a single switching point, typically, a public branch exchange (“PBX”) or in some cases a programmable switch. Despite the popularity of this conventional design, there are several problems with this kind of architecture. The problems include a single point of failure, proprietary closed architecture, and antiquated administration tools.
Conversely, telephony devices have more recently been implemented in distributed network environments, namely, Internet Protocol (IP) networks. In such systems IP telephony devices are used as end user devices (telephones) and to route data between nodes simultaneously, offering truly compelling benefits including no central point of failure, reduced tolls, essentially unlimited scalability, open architecture and user friendly administration tools. This is often called IP telephony.
Currently, IP telephony has limitations including poor quality of service. Poor quality of service for IP telephony includes, but is not limited to, packet delays or collisions which cause anomalies in the voice transmission on the receiver's end, and disconnection of the sender from the receiver due to discontinuity in the data stream. These problems can be attributed to the fact that the Internet is an unmanaged network of sub-networks with no resource allocation authority. As a result, it is common to encounter situations where there are too many users trying to communicate too much data through an already saturated pipeline. This problem is usually not present in corporate local or wide area networks since they generally have a resource allocation authority in the form of an engineer or manager. This person is usually responsible for designing a data network to have adequate bandwidth, redundant switching points, etc. However, if network traffic exceeds predicted levels in such a corporate local or wide area network, quality of service for IP telephony devices may also be poor.